Initial pure C++ implementation

src/hrtf/sofa.h

@@ -0,0 +1,61 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+#include <vector>
+
+#include "foundation/status.h"
+
+namespace joc::hrtf {
+
+// Coordinate declaration of one SOFA variable: Type ("spherical"/"cartesian") and
+// Units.  Empty when the file does not declare them (ListenerUp inherits).
+struct SofaCoordinate {
+    std::string type;
+    std::string units;
+};
+
+// SOFA SimpleFreeFieldHRIR as this project consumes it: the impulse responses,
+// the measurement geometry and the metadata needed to report what was loaded.
+// All angles are degrees, all distances metres, exactly as the file stores them.
+struct SofaHrir {
+    double sample_rate = 0.0;
+    std::uint32_t ir_count = 0;   // M: number of measurements
+    std::uint32_t ir_length = 0;  // N: taps per impulse response
+    std::vector<double> ir;       // C order [M][2][N]
+    double delay[2] = {0.0, 0.0};
+    std::vector<double> source_position;  // M*3
+    double listener_position[3] = {0.0, 0.0, 0.0};
+    double listener_view[3] = {1.0, 0.0, 0.0};
+    double listener_up[3] = {0.0, 0.0, 1.0};
+    double emitter_position[3] = {0.0, 0.0, 0.0};
+    double receiver_position[6] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0};
+    std::string conventions;
+    std::string sofa_conventions;
+    std::string convention_version;
+    std::string version;
+    std::string data_type;
+    std::string room_type;
+    std::string title;
+    std::string database_name;
+    std::string listener_short_name;
+    std::string comment;
+    std::string sampling_rate_units;
+    SofaCoordinate source_position_coordinates;
+    SofaCoordinate listener_position_coordinates;
+    SofaCoordinate listener_view_coordinates;
+    SofaCoordinate listener_up_coordinates;
+    SofaCoordinate emitter_position_coordinates;
+    SofaCoordinate receiver_position_coordinates;
+    // Identity of the file itself, needed for the compiled-cache key.
+    std::string source_path;
+    std::string source_sha256;
+
+    // One line for reports and logs:
+    // "SOFA SimpleFreeFieldHRIR, <M> IRs x <N> taps @ <rate> Hz".
+    std::string summary() const;
+};
+
+Status load_sofa(const std::string& path, SofaHrir* out);
+
+}  // namespace joc::hrtf